ALSA compress / ASoC compress / SOF: Compressed audio support with IPC4

Peter Ujfalusi <peter.ujfalusi@linux.intel.com> says:

This series adds compressed audio support for SOF with IPC4 firmware.
Supported formats are PCM, MP3, AAC and VORBIS, the feature set is
PAUSE_PUSH/RELEASE, DRAIN and position reporting.

Patches 1-5 are prerequisites in the ALSA compress core and in
soc-compress.c.

These are core fixes rather than driver level workarounds on purpose.
The other users of compressed DPCM have DSP internal ports on their
BEs, driven by code they own. An Intel/SOF BE ends at a third party
CODEC driver which is shared with the non DPCM case and has no reason
to know that the FE is compressed. That set of CODECs is open ended,
so teaching each of them to cope with a compressed FE does not scale.
The core has to hand a BE the same substream state whether the FE is
a PCM or a compressed one.

Two of these patches change behaviour for the existing users of
compressed DPCM, so they would need a look from Qualcomm and NXP:

 - "ASoC: soc-compress: Implement trigger FE-BE sequencing as with
   normal PCMs" makes the FE/BE trigger order follow
   dai_link->trigger[], the way dpcm_fe_dai_do_trigger() does it.
   Neither sound/soc/qcom/ nor sound/soc/fsl/ sets it, so both default
   to SND_SOC_DPCM_TRIGGER_PRE: START keeps the current order, but
   STOP, SUSPEND and PAUSE_PUSH now trigger the BE before the FE.

 - "ASoC: soc-compress: Stop running dpcm on free" sends a STOP trigger
   from soc_compr_free_fe() if the DPCM is still in START state, which
   is the case when the last trigger the stream received was a DRAIN.

Patches 6-20 implement the IPC4 compressed support, patch 21 is a
Kconfig cleanup. The last two patches enable the feature, in Kconfig
for TGL and later and in the topology parser, so the compressed device
type only becomes usable once the code behind it is in place.

Testing:

 - IPC4: Arrow Lake, compressed playback on speaker and headphone
   (cs42l43), MP3, AAC and VORBIS.
 - IPC3: tested by NXP. This does not cover the STOP on free path
   above, as they do not implement DRAIN.

Link: https://patch.msgid.link/20261007084955.1256-1-peter.ujfalusi@linux.intel.com

2 files changed, 2 insertions, 1 deletions

diff --git a/include/uapi/linux/alloc_tag.h b/include/uapi/linux/alloc_tag.h
index e3ad94444864..7d4618bea043 100644
--- a/include/uapi/linux/alloc_tag.h
+++ b/include/uapi/linux/alloc_tag.h
@@ -38,6 +38,7 @@ struct allocinfo_counter {
 	__u64 bytes;
 	__u64 calls;
 	__u8 accurate;
+	__u8 pad[7];
 } __attribute__((aligned(8)));
 
 struct allocinfo_tag_data {
diff --git a/include/uapi/linux/random.h b/include/uapi/linux/random.h
index 1dd047ec98a1..ef6614d9c704 100644
--- a/include/uapi/linux/random.h
+++ b/include/uapi/linux/random.h
@@ -58,7 +58,7 @@ struct rand_pool_info {
 /**
  * struct vgetrandom_opaque_params - arguments for allocating memory for vgetrandom
  *
- * @size_per_opaque_state:	Size of each state that is to be passed to vgetrandom().
+ * @size_of_opaque_state:	Size of each state passed to vgetrandom().
  * @mmap_prot:			Value of the prot argument in mmap(2).
  * @mmap_flags:			Value of the flags argument in mmap(2).
  * @reserved:			Reserved for future use.